After doing vagrant reload on a Labs-Vagrant instance (or enabling a role that forces it), it complains about ports 8080 and 443 already being in use (even though they are not, according to lsof). Changing the ports works, but only until the next reload when those too become become unusuable (and the old ones stay that way as well).
Workaround: vagrant config http_port $((`vagrant config --get http_port` 1)), vagrant config https_port $((`vagrant config --get https_port` 1)), vagrant provision, update web proxies, make sure the ports are included in the security group used by the vagrant box.